[interpreter, debugger] support debug breaks via bytecode array copy

src/interpreter/interpreter.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/interpreter.h"
 
 #include "src/ast/prettyprinter.h"
 #include "src/code-factory.h"
 #include "src/compiler.h"
 #include "src/factory.h"
@@ skipping 19 matching lines @@
   if (IsDispatchTableInitialized()) return;
   Zone zone;
   HandleScope scope(isolate_);
 
 #define GENERATE_CODE(Name, ...)                                        \
   {                                                                     \
     InterpreterAssembler assembler(isolate_, &zone, Bytecode::k##Name); \
     Do##Name(&assembler);                                               \
     Handle<Code> code = assembler.GenerateCode();                       \
     TraceCodegen(code, #Name);                                          \
-    int index = static_cast<int>(Bytecode::k##Name);                    \
-    dispatch_table_[index] = *code;                                     \
+    dispatch_table_[Bytecodes::ToByte(Bytecode::k##Name)] = *code;      \
   }
   BYTECODE_LIST(GENERATE_CODE)
 #undef GENERATE_CODE
 }
 
+Code* Interpreter::GetBytecodeHandler(Bytecode bytecode) {
+  DCHECK(IsDispatchTableInitialized());
+  return dispatch_table_[Bytecodes::ToByte(bytecode)];
+}
+
 void Interpreter::IterateDispatchTable(ObjectVisitor* v) {
-  v->VisitPointers(&dispatch_table_[0],
-                   &dispatch_table_[0] + kDispatchTableSize);
+  v->VisitPointers(
+      reinterpret_cast<Object**>(&dispatch_table_[0]),
+      reinterpret_cast<Object**>(&dispatch_table_[0] + kDispatchTableSize));
 }
 
 bool Interpreter::MakeBytecode(CompilationInfo* info) {
   if (FLAG_print_bytecode || FLAG_print_source || FLAG_print_ast) {
     OFStream os(stdout);
     base::SmartArrayPointer<char> name = info->GetDebugName();
     os << "[generating bytecode for function: " << info->GetDebugName().get()
        << "]" << std::endl
        << std::flush;
   }
@@ skipping 1655 matching lines @@
 
 // Debugger
 //
 // Call runtime to handle debugger statement.
 void Interpreter::DoDebugger(InterpreterAssembler* assembler) {
   Node* context = __ GetContext();
   __ CallRuntime(Runtime::kHandleDebuggerStatement, context);
   __ Dispatch();
 }
 
+// DebugBreak
+//
+// Call runtime to handle a debug break.
+#define DEBUG_BREAK(Name, ...)                                              \
+  void Interpreter::Do##Name(InterpreterAssembler* assembler) {             \
+    Node* context = __ GetContext();                                        \
+    Node* original_handler = __ CallRuntime(Runtime::kDebugBreak, context); \
+    __ DispatchToBytecodeHandler(original_handler);                         \
+  }
+DEBUG_BREAK_BYTECODE_LIST(DEBUG_BREAK);
+#undef DEBUG_BREAK
+
 // ForInPrepare <cache_info_triple>
 //
 // Returns state for for..in loop execution based on the object in the
 // accumulator. The result is output in registers |cache_info_triple| to
 // |cache_info_triple + 2|, with the registers holding cache_type, cache_array,
 // and cache_length respectively.
 void Interpreter::DoForInPrepare(InterpreterAssembler* assembler) {
   Node* object = __ GetAccumulator();
   Node* context = __ GetContext();
   Node* result_triple = __ CallRuntime(Runtime::kForInPrepare, context, object);
@@ skipping 76 matching lines @@
   Node* index = __ LoadRegister(index_reg);
   Node* context = __ GetContext();
   Node* result = __ CallRuntime(Runtime::kForInStep, context, index);
   __ SetAccumulator(result);
   __ Dispatch();
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8